[chromeos] Make testProfilePreservedBetweenLogins test robust

chrome/test/functional/chromeos_login.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import os
 import subprocess
 import sys
 
 import pyauto_functional  # Must be imported before pyauto
@@ skipping 189 matching lines @@
   def testProfilePreservedBetweenLogins(self):
     """Verify that profile is preserved between two login sessions.
 
     Also verify Local State.
     """
     self.testGoodLogin()
 
     # Build up some history and setup state in "Local State".
     url = self.GetHttpURLForDataPath('title2.html')
     self.NavigateToURL(url)
+    # chromeos often takes a while to register URLs into history.
+    self.assertTrue(self.WaitUntil(lambda: self.GetHistoryInfo().History()),
+                    msg='Could not open %s successfully' % url)
     open('/home/chronos/__magic__', 'w').close()
     open('/home/chronos/user/__magic__', 'w').close()
 
     def _VerifyProfile():
       history = self.GetHistoryInfo().History()
       self.assertEqual(1, len(history))
       self.assertEqual(url, history[0]['url'])
       self.assertTrue(os.path.exists('/home/chronos/__magic__'),
           msg='/home/chronos/__magic__ did not persist across login sessions')
       self.assertTrue(os.path.exists('/home/chronos/user/__magic__'),
@@ skipping 28 matching lines @@
         msg='Could not find "help_advanced" in help output.')
 
     # Exit crosh and close tab.
     self.SendKeysToHterm('exit\\n')
     self.WaitForHtermText(text='command crosh completed with exit code 0',
         msg='Could not exit crosh.')
 
 
 if __name__ == '__main__':
   pyauto_functional.Main()